Switched-fabric communication networks such as InfiniBand™ and high-speed Ethernet™ may use Completion Queues (CQs) to signal to a requestor (“client”) that network tasks have been completed. Completion Queues in InfiniBand are described, for example, in InfiniBand™ Architecture Specification, Volume 1, Release 1.2.1 Nov. 2007, pages 445 to 449; and, in Mellanox Adapters Programmer's Reference Manual (PRM), Revision 040 (2016), pages 115-132.
Techniques for reducing the size of CQs are described, for example, in U.S. Pat. No. 8,959,265, which is incorporated herein by reference.